1. Field of the Invention
The invention relates to a capped electric lamp for operation at mains voltage, comprising:
a lamp vessel which is vacuum sealed and has an end portion which is fused to a stem tube which projects into the lamp vessel and surrounds an exhaust tube;
an electric element in the lamp vessel connected to current supply conductors which extend to the exterior alongside the exhaust tube;
a lamp cap provided with a shell having an axis, a first end of the shell being fixed around the said end portion of the lamp vessel with an adhesive compound, and a second end of the shell being coupled to an insulator body;
contact pins fixed in the insulator body and extending to the exterior therefrom for connection to respective current supply conductors.
The invention also relates lamp cap unit suitable for use in the lamp according to the invention.
A lamp of the kind described in the opening paragraph and suitable for operation at low power is known from U.S. Pat. No. 2,730,689, issued Jan. 10, 1956. Such lamp has the disadvantage that a lampholder is required for mounting the lamp against a surface, for example against a wall of an electric appliance such as, a refrigerator or a microwave oven. Moreover, the lamp provides no points of application for positive retention by a lampholder. It can be held only by its contact pins.
Another disadvantage of the known lamp is that the current supply conductors must be passed between the legs of respective contact pins, which each consist of a metal strip curved in a hairpin shape, during assembly of the lamp vessel with the lamp cap. Then, the lamp cap must be affixed around the lamp vessel. During this assembly, the current supply conductors must pass on further between the legs of the contact pins of their own accord. If they do not, there is a great risk of short-circuiting inside the lamp cap. Subsequently, the contact pins are flattened, by which contact with the current supply conductors is to be achieved. Such a contact is unreliable in the event of corrosion of the supply conductors and/or the contact pins.